ΔE 14.4, fair: the same colour family, but not a straight swap. Russ. AF Light Blue is a little darker, more saturated than Underbelly Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Russ. AF Light Blue is a little darker, more saturated than Underbelly Blue.
The same difference applies the other way round: Underbelly Blue is a little lighter, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Underbelly Blue on the colour wheel See Russ. AF Light Blue on the colour wheel
All matches: Underbelly Blue equivalents · Russ. AF Light Blue equivalents